1. Field of the Invention
The subject invention relates to an increased efficiency counter-rotating electric motor that, upon demand, converts into a traditional electric motor, thereby producing a device that operates in efficient power output ranges at both slow rpm and high rpm circumstances. Specifically, the subject invention utilizes a counter-rotating electric motor in which both an armature or inner rotational member and a stator or outer rotational member rotate in opposite directions during operation. Generally, the subject motor is configured as a separate motor (that may be mounted in a vast variety of motor-containing systems as desired) with two oppositely rotating output drives or for a vehicle is mounted at the center of one wheel (hub motor) of the selected wheeled vehicle, wherein the armature output drive means is attached to and extends from the armature of the hub motor to either the same wheel or a second wheel of the vehicle and a wheel and tire extends from the stator of the subject hub motor and includes a rotation reversal means for the armature to produce a common rotational direction for both the stator and armature to drive the vehicle. For example, with an adapted bicycle, the counter-rotating hub motor may be located in the rear wheel and configured so that the outer rotational member (stator) directly powers the wheel containing the hub motor and the inner rotational member (armature) indirectly powers the same wheel, but after its rotational direction is reversed and coupled back into the outer rotational member. Also, for example, with an adapted tricycle, the counter-rotating hub motor may be located in one of the rear wheels and configured so that the outer rotational member (stator) powers the wheel containing the hub motor and the inner rotational member (armature) powers the second rear wheel (the one without the hub motor).
As indicated, both the armature (inner rotational member) and the stator (outer rotational member) rotate, in opposite directions, thereby minimizing the creation of heat during operation and accessing torsional forces normally lost by utilizing a traditional motor in which the stator is fixed within the motor housing and the armature rotates (or the armature is fixed and the stator rotates in other equivalent configurations like a hub motor).
Included in the subject invention is means to brake/stop the rotation of the armature (or stator, if so desired), thereby converting the counter-rotating motor into a traditional motor in which only one element rotates (again, depending on the desired configuration either the outer/stator rotational member or the inner/armature rotational member). Again using a powered vehicle as an example, the benefit of this dual-mode functioning ability is that at slower vehicle speeds the high efficiency and high torque output operational mode of the counter-rotating motor is utilized and when a higher vehicle speed is desired the subject system may be converted into a traditional motor by halting the rotation of one of the rotating members (for a hub motor the armature is stopped, thereby directing all of the output force directly to the stator/wheel).
2. Description of Related Art
For a traditional brush-containing DC motor, the outside/surrounding motor housing is stationary, as is the stator/field magnets within the housing. Normally, the stator is usually affixed to the housing. An internal armature/rotor is attached to a shaft or axle that rotates during operation (in some versions of a standard motor the rotor may be termed the armature). Thus, the armature shaft/axle extends out from the stationary motor housing and rotates when electrical current is applied to the motor (the armature/rotor rotates within the stationary stator/field magnets). In brush-containing motors, physical brushes are required to transmit the electricity from the outside source to the rotor via a commutator interfacing that pulses the current to alternate the field polarity in the coils of the armature, thereby generating the rotational driving force used to turn the armature. The history of traditional brush-containing electric motors is extensive and one version is found at www.sparkmuseum.com/MOTORS.HTM.
For a traditional brushless DC motor, the outside/surrounding motor housing is, again, stationary, as is the stator within the housing. Normally, the stator is usually affixed to the housing. An internal armature/rotor is attached to a shaft or axle that rotates during operation. Thus, the armature shaft/axle extends out from the stationary motor housing and rotates when electrical current is applied to the motor (the armature/rotor rotates within the stationary stator/field magnets). In brushless motors, physical brushes are not required to transmit the electricity from the outside source to the rotor. The configuration of brushless motors permits either a design utilizing permanent magnets affixed to the stator or, more commonly, the permanent magnets are associated with the armature and the field windings are located in the stationary stator. Clearly, brushless motors do not use physical brushes for commutation; instead, they are electronically commutated by standard techniques. To produce rotational movement, suitably pulsed currents are delivered to the windings and timed via incorporated means such as the application of standard Hall Effect sensors/magnets, back emf, and equivalent means. Brushless DC motors have many well-known advantages over brush-containing motors.
Even though an extremely limited number of specialty counter-rotating brush-containing DC motors are described in published patents (see immediately below), it is stressed that no references have been discovered that utilize, suggest, hint, teach, or imply a counter-rotating electric DC motor that operates via a brushless technology in which both the armature (inner rotational member) and the stator (outer rotational member) physically rotate in opposite directions while maintaining continuous electrical contact with exterior control and power elements.
A counter-rotating electric DC motor is described in related U.S. Pat. Nos. 2,431,255, 2,456,993, and 2,462,182. The disclosed motor was to be used in torpedo propulsion systems in which a coaxial propeller assembly drove separate propellers in opposite directions to aid in keeping the torpedo traveling in a desired direction. Clearly, the operational lifetime of such a motor is extremely limited, given its destruction upon hitting a target. To eliminate necessary centrifugal/centripetal influenced commutator-to-brush contact breaks created while the stator is rotating (normally the stator is not rotating so a constant resilient means or spring simply forces a brush inward and towards the center of rotation, thereby contacting the commutator for the required electrical communication, but rotation of the stator causes the brushes to “float” away from the commutator), the device contained a “radial commutator” (a disk extending outwardly from the axis of rotation) and contact brushes directed parallel to the axis of rotation. This radial commutator/brush design is complex, not easily fabricated, and, thus, expensive to manufacture.
In U.S. Pat. No. 3,738,270 a brushless electric DC motor for a torpedo is disclosed. To maintain stability during its course in water to its target, oppositely rotating propellers are beneficial. The design utilizes a stationary stator around which two independent armatures rotate in opposite directions to drive the associated propellers in corresponding opposite directions.
U.S. Pat. No. 4,056,746 presents a counter rotation electric motor that is quite similar to the design present immediately above ('270). Once again a radial commutator/brush design is utilized in the operation of the device. An interesting analysis of the benefits of a counter-rotating motor is presented: 1) increasing the field cutting speed of the armature to increase power output of the motor; 2) minimizing field collapse; and 3) maintaining the angular rate of the armature which is compatible with the containment of the generated centrifugal forces. There is no discussion, suggestion, implication, or teaching that the related motor was more efficient in using less input energy and producing more output work. It is stressed that it has been discovered that the subject invention dramatically increases the efficiency of subject counter-rotating motor.
A DC rotary machine is related in U.S. Pat. No. 4,259,604. The commutator/brush design in this device is very simplistic and is not created to operate at high rotational velocities. Typically, the motor is used in a machine such as a tape recorder, VTR, and the like that need low rotational speeds. The commutator is of standard cylindrical design and the brushes are contacted in a permanent fashion against the commutator bars.
U.S. Pat. No. 4,375,047 presents a torque compensating electrical motor. This device is comprised of two motors, either next to one another in a serial connection or inside one another. The armature is attached to the axle and is utilized for output work. The stator rotates, but is attached to nothing but the supporting bearings, and is spinning to simply eliminate internal torque and not to produce work. The subject invention utilizes both the rotating armature and the rotating stator to generate work. A critical difficulty exists in this patent since the electrical connection are not described or discussed, except to say that the “motor control are well known and do not form part of the present invention” which is simply not a true and valid statement. The figures show only truncated wires coming from the field coils with no details concerning connection to “outside” power and control means. When counter-rotation of motor components is part of the operation of the device the means for electrical communication is critically important and extremely difficult to achieve. Apparently, the reference to “well known” implies some sort of undisclosed brush/commutator configuration (given the 1983 issue date) or a merely theoretical and non-enabled invention was related.
A rotating-field machine is described in U.S. Pat. No. 4,645,963. In this device, which is extremely similar to '047 immediately above, again, the armature is attached to the axle and is utilized for output work. The stator rotates, but is attached to nothing but the supporting bearings, and is spinning to simply rotate the field and not to produce work. Once again, the subject invention utilizes both the rotating armature and the rotating stator to generate work.
U.S. Pat. No. 5,067,932 discloses a dual-input motor in which two armatures rotate either together or in opposite directions within a stationary/fixed outer stator. The stator is rigidly affixed to a suspension member or other stationary anchor.
A dual rotary AC generator is described in U.S. Pat. No. 5,089,734. This disclosure presents, basically, a motor run in reverse, thereby becoming a generator in which both the magnetic field and armature rotate in opposite directions. Unfortunately, the manner in which the device receives or delivers electricity is not related, nor are any internal electrical components described.
U.S. Patent Publication No.: 2006/0163963 discloses a counter rotating generator. Once again, a radially disposed set of disks are utilized in the commutator/brush design. In this case, the slip rings have a relatively large diameter (which is claimed to decrease heat production) and contact brushes in a continual manner, with constant force, regardless of rotational speed. Additionally, the described generator is used in relatively slow RPM situations in which the wind or manual cranking are utilized as the driving forces, unlike the subject invention that may be operated from relatively low to relatively high RPM values.
Disclosed in “Counter-Rotating Permanent Magnet Brushless DC Motor for Underwater Propulsion,” J. Qiu et al., IPEMC 2006 is a “theoretical” counter-rotational motor that was discussed via a test-bed that comprised two standard motors that rotated in opposite directions (an “attempt” to mimic a physically real counter-rotational motor). An extremely complex set of Hall Effect Sensors was theorized as being necessary to operate their motor, should an actual motor be fabricated, which did not occur. Additionally, slip-ring connectors were theorized as a means for electrical connections.
A brush-containing motor is related in two generally theoretical papers from Japan. A device labeled as an “Anti-Directional-Twin Rotary Motor” is described that utilizes multiple brushes and slip rings of considerable size to power the outer rotor or as the authors state “the size of the slip ring is not negligible.” The analysis of their brush-containing motor presents and relies on many theoretical estimations and adjustments to the very limited data that was recorded. It is of particularly note that “the stator resistance was adjusted so that the theoretical torque-speed curve might fit the measured curve. No comments or comparisons of any sort are made or suggested between their twin-rotor motor and a motor in which one of the rotors is stopped. Clearly, due to the difficulty of actually operating their multi-brush/slip ring motor, much of the presented/plotted data is not actual physical collected data for a twin-rotor motor but “estimated” data from “equivalent” situations. Also, it is plainly stated that the incorporation of the brush/slip ring containing means decreases efficiency by at least 20%. The papers are: “Anti-Directional-Twin-Rotary Motor Drive for Electric Vehicles” by Atsuo Kawamura, et al., page 453, 1994 IEEE (0-7803-1993-1/94© 1994 IEEE) and “Analysis of Anti-Directional-Twin-Rotary Motor Drive Characteristics for Electric Vehicles” by Atsuo Kawamura, et al., IEEE Transactions on Industrial Electronics, Vol. 44, No. 1, February 1997 (0278-0046/97© 1997 IEEE).
Finally, a purely “theoretical” brush containing motor with a rotational stator is presented in expired U.S. Pat. No. 6,433,451. On its face, this is a completely non-functional and imaginary invention. This issued patent is, literally, filled with dozens of major errors, including: inconsistent statements; wrong/inappropriate equations; incorrectly and incompletely drawn figures; elements listed as being in the figures and not actually presented in the figures; and mechanically/electrically impossible configurations for the theoretical motor. Brushes are clearly present in both FIGS. 1 and 2, yet the statement “[in FIG. 2] the new points for coupling of the mobile stator coils are 23 and 24” does not correspond to the numbers 23 and 24 being presented in any of the figures. The statement “the proposed motor” plainly indicates a theoretical motor was never constructed since what is shown in the figures would not come close to actually functioning or even being capable of one rotation (as is obvious from the figures, components would physically run into one another upon rotation). Additionally, the “electrical distributor 8” is not defined and the common definition of the term “distributor” presents an incorrect element. Further, the “Formulas Refresher” table presents a somewhat unrelated group of equations that are, mostly, utilized for linear motion and not appropriate in an analysis of rotational motion. Unfortunately, this patent was allowed to issue with all of the gross errors, untrue statements, and incorrect analysis.